Artificial intelligence-assisted repurposing of lubiprostone alleviates tubulointerstitial fibrosis

Tubulointerstitial fibrosis (TIF) is the most prominent cause which leads to chronic kidney disease (CKD) and end-stage renal failure. Despite extensive research, there have been many clinical trial failures, and there is currently no effective treatment to cure renal fibrosis. This demonstrates the necessity of more effective therapies and better preclinical models to screen potential drugs for TIF. In this study, we investigated the antifibrotic effect of the machine learning-based repurposed drug, lubiprostone, validated through an advanced proximal tubule on a chip system and in vivo UUO mice model. Lubiprostone significantly downregulated TIF biomarkers including connective tissue growth factor (CTGF), extracellular matrix deposition (Fibronectin and collagen), transforming growth factor (TGF-β) downstream signaling markers especially, Smad-2/3, matrix metalloproteinase (MMP2/9), plasminogen activator inhibitor-1 (PAI-1), EMT and JAK/STAT-3 pathway expression in the proximal tubule on a chip model and UUO model compared to the conventional 2D culture. These findings suggest that the proximal tubule on a chip model is a more physiologically relevant model for studying and identifying potential biomarkers for fibrosis compared to conventional in vitro 2D culture and alternative of an animal model. In conclusion, the high throughput Proximal tubule-on-chip system shows improved in vivo-like function and indicates the potential utility for renal fibrosis drug screening. Additionally, repurposed Lubiprostone shows an effective potency to treat TIF via inhibiting 3 major profibrotic signaling pathways such as TGFβ/Smad, JAK/STAT, and epithelial-mesenchymal transition (EMT), and restores kidney function.

Identification of the Main Chemical constituents and mechanism of Renshen Guben oral liquid against Renal Fibrosis

BACKGROUND

Renal fibrosis is the late stage of many chronic kidney diseases (CKD). Clinically, there is almost no effective treatment for renal fibrosis except dialysis. Renshen Guben oral liquid (RSGB) is a Chinese patent medicine approved by National Medical Products Administration (NMPA), which is suitable for clinical patients with chronic nephritis. Currently, the chemical constituents of RSGB remains unclear, and its efficacy and mechanism on renal fibrosis have not been reported.

METHODS

In our research, ultra-high performance liquid chromatography/quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS/MS) was employed to describe the chemical profile of RSGB, unilateral ureteral obstruction (UUO) model in mice was established to evaluate the beneficial effect of RSGB on renal fibrosis by biochemical indexes, HE and Masson staining. RNA sequencing and "constituents-targets-pathways" multi-dimensional network was established to mine the mechanisms of RSGB. Key targets were verified by quantitative real-time PCR (qRT-PCR) and western bolt (WB).

RESULTS

A total of 201 constituents were identified or tentatively characterized, 15 of which were confirmed with standards. The number of triterpenes was the highest with 49, followed by phenols with 46. RSGB ameliorated the blood urea nitrogen (BUN) and serum creatinine (Scr) levels in serum, normalizing pathological structure of kidney tissue. RNA sequencing revealed that RSGB regulates 226 differential genes, which were involved in kidney development. According to the "constituents-targets-pathways" network, 26 key active constituents may mainly regulate the inflammatory immune system through 88 corresponding targets. qRT-PCR and WB results showed that RSGB inhibited the activation of the Tgfβ1/Smad2/3 pathway, Wnt4/β-Catenin pathway and NGFR/NF-κB pathway.

CONCLUSIONS

Overall, our study, for the first time, characterized 201 chemical constituents in RSGB, and 26 of them were screened out to alleviates renal fibrosis mainly through Tgfβ1/Smad2/3 pathway, Wnt4/β-catenin pathway and NGFR/NF-κB pathway, which may provide a new research strategy for research on the mechanism of traditional Chinese Medicine.

TGF-β1 receptor blockade attenuates unilateral ureteral obstruction-induced renal fibrosis in C57BL/6 mice through attenuating Smad and MAPK pathways

Renal fibrosis is characterized by accumulation of extracellular matrix components and collagen deposition. TGF-β1 acts as a master switch promoting renal fibrosis through Smad dependent and/or Smad independent pathways. Thirty-five male C57BL/6 mice were divided into five groups of seven each; sham, unilateral ureteral obstruction (UUO), UUO+galunisertib (150 and 300 mg/kg/day), galunisertib (300 mg/kg/day). The UUO markedly induced renal fibrosis and injury as indicated by renal functional loss, increased levels of collagen Iα1, fibronectin and α-SMA; it also activated both the Smad 2/3 and MAPKs pathways as indicated by increased levels of TGF-β1, p-Smad 2, p-Smad 3, p-p38, p-JNK and p-ERK. These UUO-induced changes were markedly attenuated by oral administration of galunisertib, the TGFβRI small molecule inhibitor. In conclusion, we demonstrated that TGF-β1 receptor blockade can prevent UUO-induced renal fibrosis through indirect modulation of Smad and MAPKs signaling pathways and may be useful as a therapeutic agent in treatment and/or prevention of renal fibrosis.

Axl-inhibitor bemcentinib alleviates mitochondrial dysfunction in the unilateral ureter obstruction murine model

Renal fibrosis is a progressive histological manifestation leading to chronic kidney disease (CKD) and associated with mitochondrial dysfunction. In previous work, we showed that Bemcentinib, an Axl receptor tyrosine kinase inhibitor, reduced fibrosis development. In this study, to investigate its effects on mitochondrial dysfunction in renal fibrosis, we analysed genome‐wide transcriptomics data from a unilateral ureter obstruction (UUO) murine model in the presence or absence of bemcentinib (n = 6 per group) and SHAM‐operated (n = 4) mice. Kidney ligation resulted in dysregulation of mitochondria‐related pathways, with a significant reduction in the expression of oxidative phosphorylation (OXPHOS), fatty acid oxidation (FAO), citric acid cycle (TCA), response to reactive oxygen species and amino acid metabolism‐related genes. Bemcentinib treatment increased the expression of these genes. In contrast, AKT/PI3K signalling pathway genes were up‐regulated upon UUO, but bemcentinib largely inhibited their expression. At the functional level, ligation reduced mitochondrial biomass, which was increased upon bemcentinib treatment. Serum metabolomics analysis also showed a normalizing amino acid profile in UUO, compared with SHAM‐operated mice following bemcentinib treatment. Our data suggest that mitochondria and mitochondria‐related pathways are dramatically affected by UUO surgery and treatment with Axl‐inhibitor bemcentinib partially reverses these effects.

WNT1-inducible-signaling pathway protein 1 regulates the development of kidney fibrosis through the TGF-β1 pathway

Fibrosis is a pathological feature of chronic kidney disease and its progression correlates with declining renal function. Kidney fibrosis is driven by multiple profibrotic factors. This project examined the regulatory function of WNT1-inducible-signaling pathway protein 1 (WISP1) in the development of kidney fibrosis. Induction of WISP1 by transforming growth factor beta 1 (TGF-β1), and the role of WISP1 in TGF-β1/Smad signaling and fibrotic responses, was examined in multiple kidney cells. Kidney expression of WISP1 was examined in mouse models of unilateral ureter obstruction (UUO) and streptozotocin-induced diabetic nephropathy. WISP1 antibody was administered to UUO mice during the induction of kidney injury and the impact on kidney fibrosis was examined. WISP1 expression was upregulated in both mouse models. TGF-β1-induced expression of WISP1 and profibrotic genes in cultured kidney cells via TGF-βR1. Recombinant WISP1-induced expression of TGF-βR1 in kidney cells. Suppression of WISP1 by shRNA or neutralizing antibody reduced TGF-β1-mediated activation of Smad3, fibrotic gene expression, and fibroblast proliferation. Treatment with WISP1 antibody inhibited the development of kidney fibrosis in UUO mice. WISP1 mediates the profibrotic effects of TGF-β1 in kidney cells and in kidney disease. Pharmacological blockade of WISP1 exhibits potential as a novel therapy for inhibiting kidney fibrosis.

Ribes diacanthum Pall (RDP) ameliorates UUO-induced renal fibrosis via both canonical and non-canonical TGF-β signaling pathways in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Ribes diacanthum Pall (RDP), a folk medicine, has been widely used in Mongolia to treat urinary system diseases.

AIM OF THE STUDY

To investigate the effectiveness of RDP on unilateral ureteral obstruction (UUO)-induced renal interstitial fibrosis and the underlying mechanisms.

MATERIALS AND METHODS

A total of 60 mice were randomly divided into six groups: sham group, sham plus RDP (40 mg/kg) group, UUO model group, and UUO model plus RDP (10, 20 or 40 mg/kg) groups. After surgery, aqueous extract of RDP were administrated intragastrically (i.g) daily for a week and ipsilateral kidneys were collected seven days after surgery. Levels of blood urea nitrogen (BUN) and serum creatinine (Scr) were detected to reflect the kidney injury. Hematoxylin & eosin and Masson's trichrome staining were used to evaluate the kidney morphological changes and fibrosis, respectively. ELISA was used to examine the levels of pro-inflammatory cytokines. Immunohistochemistry, western blot and PCR were used to examine the expression levels of key proteins involved in transforming growth factor (TGF-β)/Smad and mitogen-activated protein kinase (MAPK) signaling pathways.

RESULTS

RDP treatment attenuates the level of BUN and kidney fibrosis in UUO mice, decreases the expressions of interleukin-6, tumor necrosis factor-α, Interleukin-1α, TGF-β1, monocyte chemotactic protein-1, α-smooth muscle actin, collagen I, fibronectin, and vimentin, while increases the expressions of E-cadherin and hepatocyte growth factor. Moreover, RDP administration significantly decreases the levels of p-Smad2/3, p-ERK1/2, p-p38 and p-JNK, while increases the expression level of Smad7 in UUO models.

CONCLUSION

These data demonstrate that RDP ameliorates renal fibrosis through TGF-β/Smad and MAPK pathways in a UUO mouse model.

The TGFβ-ERK pathway contributes to Notch3 upregulation in the renal tubular epithelial cells of patients with obstructive nephropathy

Renal interstitial fibrosis is a common renal injury resulted from a variety of chronic kidney conditions and an array of factors. We report here that Notch3 is a potential contributor. In comparison to 6 healthy individuals, a robust elevation of Notch3 expression was observed in the renal tubular epithelial cells of 18 patients with obstructive nephropathy. In a rat unilateral ureteral obstruction (UUO) model which mimics the human disease, Notch3 upregulation closely followed the course of renal injury, renal fibrosis, TGFβ expression, and alpha-smooth muscle actin (α-SMA) expression, suggesting a role of Notch3 in promoting tubulointerstitial fibrosis. This possibility was supported by the observation that TGFβ, the major renal fibrogenic cytokine, stimulated Notch3 expression in human proximal tubule epithelial HK-2 cells. TGFβ enhanced the activation of ERK, p38, but not JNK MAP kinases in HK-2 cells. While inhibition of p38 activation using SB203580 did not affect TGFβ-induced Notch3 expression, inhibition of ERK activation with a MEK1 inhibitor PD98059 dramatically reduced the event. Furthermore, enforced ERK activation through overexpression of the constitutively active MEK1 mutant MEK1Q56P upregulated Notch3 expression in HK-2 cells, and PD98059 reduced ERK activation and Notch3 expression in HK-2 cells expressing MEK1Q56P. Collectively, we provide the first clinical evidence for Notch3 upregulation in patients with obstructive nephropathy; the upregulation is likely mediated through the TGFβ-ERK pathway. This study suggests that Notch3 upregulation contributes to renal injury caused by obstructive nephropathy, which could be prevented or delayed through ERK inhibition.